The present invention relates to tool sockets, and in particular to tool sockets preferably for impact wrenches.
In the industry impact wrenches are still very popular and especially for the smaller nut sizes. However, impact wrenches are extremely inaccurate when it goes to torque repeatability or torque accuracy. Therefore, in many cases, the fastener for example a nut is impacted down and then tightened to torque with a torque wrench. This is inconvenient, since it takes more time and requires the use of two tools for one job.
It is known to provide corresponding mechanisms which are built in the drive portion of power tools. This means however the disadvantage that the tools multiple and repeated use weakens the mechanism so that it becomes unreliable. In addition, since the drive portion of the power tool is usually contained in a housing, the gear teeth of such a mechanism require frequent replacement due to the limited square inch engagement possibilities.
Accordingly, it is an object of present invention to provide a tool socket of the above mentioned general type which avoids the disadvantages of the prior art.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a tool socket which has a tool-associated element provided with first connecting means formed to connect the first tool-associated element with a tool to be turned by the tool, a second fastener-associated element provided with second connecting means for connecting the second fastener-associated element with a fastener to be tightened and loosened, the tool-associated element and the fastener-associated element having faces directed toward one another; engaging means for engaging the first tool-associated element and the second fastener-associated element with one another so that when said first tool-associated element is turned by the tool it turns said second fastener-associated element, said engaging means including gear teeth provided on the faces of the tool-associated element and the fastener-associated element; and holding means operative for holding the engaging means and therefore the tool-associated element and the fastener-associated element in engagement with one another and having a holding force limit such that when a resistance of a fastener exceeds a predetermined value said first and second elements disengage from one another and said first tool-associated element continues turning while said second fastener-associated element remain stationary.
The tool socket in accordance with the present invention provides the highly advantageous results, since it is composed of two elements which are connected with one another engageably and disengageable under certain conditions of operation. This is principally new and contradicts the long standing approach in the industry which has been maintained for decades. Usually tool sockets are very rigid, high strength, integral elements which have to transmit tremendous torques to the fasteners. The present invention departed from the long established prejudice and provides a new tool socket which is unobvious and highly advantageous.
With the present invention each socket can be used for one nut size only, and even if the hex inserts are being used, it is limited to a maximum 3 hex or 12-point sizes due to radial application problems resulted from the size reduction. Therefore, a given tool socket size is used much less frequently than the power tool that turns it. Since the gear teeth are located on the circumference of the inner walls of the tool socket and their depth is equivalent to the wall thickness of the socket, the square inch displacement is drastically improved. A further important advantage is that the invention becomes more accurate simply because unlike a drive of a power tool which is subject to torsion and subject to a drive engagement with a prior art socket, the tool socket of this invention is directly connected with the nut to be turned. A further advantage over the prior art is that a tool with such a tool socket can be manufactured relatively simply, thus reducing the cost over other torque-controlled tools.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.